Fix invalid docker-compose.yml when Beszel is installed with local Caddy

Confirmed live: "networks.beszel-agent additional properties ... not
allowed" — the root-level networks: block (_CADDY_NET_SECTION) was
placed between the two services instead of after both. Since it sits
at 0 indentation, YAML parsed the following beszel-agent: line as a
continuation of the networks: mapping instead of a new services: entry,
so the whole beszel-agent service definition got swallowed as if it
were a (invalid) child of networks.caddy_net. gatus.sh's identical
_CADDY_NET_BLOCK/_CADDY_NET_SECTION pattern never hit this because it
only ever has one service, so the same placement is always the last
content in the file there.

Moved _CADDY_NET_SECTION (the root-level networks: definition) to
after both services; _CADDY_NET_BLOCK (the per-service "join
caddy_net" snippet) stays right after the hub's own volumes, where it
correctly nests under the beszel: service only.

Verified by regenerating the compose file with local Caddy present and
parsing it with PyYAML: services.beszel and services.beszel-agent are
now proper siblings, beszel-agent keeps its image/environment/volumes
keys, beszel's own networks: is scoped to just that service, and the
root networks: definition is separate and correctly placed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H4k6J1qXXyYxhGEgnJaMvn

services/beszel.sh

@@ -259,7 +259,7 @@ services:
     volumes:
       - ./beszel_data:/beszel_data
       - ./beszel_socket:/beszel_socket
-${_CADDY_NET_BLOCK}${_CADDY_NET_SECTION}
+${_CADDY_NET_BLOCK}
   beszel-agent:
     image: henrygd/beszel-agent:latest
     container_name: beszel-agent
@@ -275,6 +275,7 @@ ${_CADDY_NET_BLOCK}${_CADDY_NET_SECTION}
       - ./beszel_agent_data:/var/lib/beszel-agent
       - ./beszel_socket:/beszel_socket
       - /var/run/docker.sock:/var/run/docker.sock:ro
+${_CADDY_NET_SECTION}
 BESZEL_COMPOSE
 
     # APP_URL only matters for the hub's own generated links and origin